what minimum system requirements need Panda3D to work 
You need a PC. And it helps to have a 3-D graphics card. 
It doesn’t really make sense to talk about minimum requirements in that sense. Panda3D is not a game, it’s a graphics engine, and there’s no real minimum requirements on the engine itself. That’s not to say that a game written with Panda won’t have minimum requirements.
Now, if you were to ask a more specific question, something like “how much hardware do I need to have in order to render 100,000 triangles per frame and maintain 60 Hz”, we could begin to answer you. Although in practice, even for a question like that, the answer is still a big “it depends”–it depends on the exact nature of your 100,000 triangles, the structure of your scene graph, the amount of additional CPU your application requires, and a hundred other factors.
David